Mastellone Hermanos S.A. (mostly known for its trade name: La Serenísima) is an Argentine dairy company headquartered in the city of General Rodríguez in Buenos Aires Province.

[4] Pascual Mastellone, son of founder Antonio, had a long tenure of chairman of the company taking over La Serenísima for more than 50 years from 1952 until 2013, when he retired due to health problems.

[1] Italian immigrant Antonino Mastellone, a cheese-maker from Sardinia who arrived in Argentina in 1925, started producing mozzarella and ricotta in his home of General Rodríguez, a pampas city west of Buenos Aires.

Mastellone delivered the products himself to Buenos Aires by train, selling it in La Boca, Barracas, and San Telmo neighborhoods, where most part of Italian immigrants had settled and were consumers of those cheeses.

The battalion itself had been named for the medieval Republic of Venice, which was widely known as La Serenissima (though the word also translates as the "most serene," or peaceful).

[10] La Serenísima also introduced large-scale organic dairy farming in Argentina, in 1994, and became the first to fortify its products with iron sulfate.

[7] In 1994, La Serenísima began selling not-from-concentrate, perishable juices through a joint venture with Tropicana (then owned by Seagram).

It was a natural partnership between Argentina's largest dairy company (with perishable product distribution capabilities and expertise) and the world's best known premium juice brand.

[7] La Serenísima, which processed over 4.8 million tons of milk annually,[7] was recognized as one of the world's most prestigious names in its sector by Global Marketing Research, in 2004.